Electrical condenser



April 14, 1931. s. s. cR'AMER 1,800,719

ELECTRICAL CONDENSER Filed Jan. 15, 1929 I2 26 34 3/ l4 l5 7 7 Ham" 9 INVENTOR sr/wu'r s. CRAMER ATTORNE 4 Patented Apr. 14, 1931 STANLEY 8. CBAMER, OI HADDON HEIGHTS,

DENSEB comm, OI CAMDE N,

NEW JERSEY me on. connnusrm Application filed January 15, 1929. Serial 170. 332,700.

This invention relates to improvements in the detailed construction of electric condensers of the variable type, such as used in radio receiving sets. g

My improvements are illustrated (in the accompanying drawing forming a part of the specification as applied to a group of condenser units which are arranged and carried by a unitary frame-work structure.

Where the condenser this manner, operate all of the condensers simultaneously.

Where all of the tuning condensers in a radio receiving set are operated by. single control devices it is .very essential that each condenser be at the proper setting so as to bring each of the turned circuits to substantially the maximum point on the resonance curve for the frequency or wave length 2 of the station being tuned in on the receiving set.

.It is therefore a big problem to get' a plurality of condensers operated by a common control, set so as to produce the most eflicient and maximum result in the tuning of their respective circuits. I have found that where plain bearings are used for the rotor system, it is very hard to get these arings in perfect alignment, especially where three and four condensers are arranged in one gang, and that the manufac-' turing discrepancies set up mechanical stresses in the frame-work which displace one or more of the condenser units sufliclent- 1y to interfere with the proper tuning of the electrical circuits with which the condenser is associated. Keeping in mind-the fact that the capacity of these air condensers is small it will be readily appreciated that 40 a slight shifting of the relative position of a group of rotor plates with respect to the stator plates, will change the 'tuning characteristics of the condenser unit, and instead of all of the circuits being tuned to maximum 'efliciency, one or more of them will be ofi the maximum point of the resonance curve. e

It has been proposed to use certain electrical compensatin devices in an endeavor 80 to overcome these maccuraeies in manufacunits are arranged ina single dial control serves to the line 66 of ture, and some success has been accom lished along this line and one or more 0 these electrical compensating features are disclosed herein. However, from tests which I have made, I have found that far better results are obtained by the journalling construction herein disclosed.

It is therefore the principal object of my invention to overcome in the construction of a gang condenser, the mechanical'difiiculties hereinbefore referred to. While accom-i NEW JERSEY, ASSIGNOR TO RADIO CON- plishing the v principal object of my invention, it is another object to provide a simple and relatively. inexpensive means for accomplishing the main purpose of the invention which will be readily understood by reference to the annexed drawing, wherein:

Figure -1 is a plan view of a four-gang condenser with the 1 rotor system fully in mesh with the stator system.

Figure 2 is a side'elevation of Fi re 1.

Figure 3. is an end view of the le -hand end of Figures 1 and 2.

Figure 4 is a section on the line 44 of igure 2. Figure 5 is a perspective view of a modified form of a combination compensating and friction applying device.

Figure 6 is an enlarged sectional view on Figure 3.

Figure 7 is an enlarged view on the lines;

77 of Figure 1.

Figure 8 is a plan view of an individual separable bearing which may be used for the purposes hereinafter set forth. I 4

Figure 9 is a vertical-sectional elevation of Figure 8.

Figure 10 is a view similar to Figure 8 taken from the reverse side, but showing a modified form of mounting the bearing member.

Figure 11 is a view similar to Figure 6,

but of a modified form on a reduced'scale from that of Figure 6.

Figure 12 is a plan view of a" further modified form of holding plate.

Referring now to the details whereinlike numbers-refer to the, corresponding parts in the various views, 1 is a frame-work having end support members 2 and 3, all pref- An adjusting device in the form of a screw erably of stee I l and somewhat trough-shaped. As shown in Figure 3, the end support members 2 and 3 are separate from the frame-work 1, but held thereto by projections 1 which extend through themembers 2 and 3 and have their ends upset or spread as indicated by the lines 5. It is to be understood of course, that the entire frame-work may be drawn out of one piece.

Bothsides of the frame-work 1 are provided with openings 6, and positioned in each of these openings, is an insulator 7 of suitable material, the insulator7 beingfastened to the frame as by screws 8. The stator plates 9 of each condenser, are fastened together by tie bars 10 which are fastened to the insulator 7 in any suitable manner as by screws 11. Thus each stator group is carried on the frame 1 by means of these insulators 7 The rotatable system includes a shaft 12' of suitable material, to which are attached sleeves 13, these sleeves being held in position on the shaft 12 in any satisfactory manner as by screws 14:. Each of the sleeves 13 carries a group of rotor plates 15, the outer ends of which are held together in a permanent position by tie bars 16. Asshown in Figure 1, only the outer rotor and stator plates of each unit are illustrated.

To eliminate the difficulties encountered with plain bearin s as set forth in the early part of this speci cation, T have devised the following construction:

As shown in Figure 1, I form onjeach of the end support plates 2 and 3, seats or races 17 for anti-friction devices such as balls 18. To cooperate with the race 17, I provide the shaft 12 adjacent the dial end, with a groove 19 which is formed by a special tool. On the rear end support member 2, I attach in any satisfactory manner, as by screws20, a cover plate 21. The plate 21 covers the race 17 and at the same time serves to hold an engagement member 22 in position against the balls 18. As it is'seen in Figure 6, the member 22 has its outer edge formed into arim 23 to lap over the outer periphery of the balls 18.

The extreme inner end of. the shaft 12 is specially formed by a suitable tool into a race 24 which cooperates with the seat 17.

25 and lock nut'2 6 is used to hold the shaft 12 in proper longitudinal alignment, so that system in mimmum and there are no 'slde or lateral,

the balls 1.8-in'the front and rear races are in proper working position. This construction provides a support forthe rotatable which friction is reduced to a strains onthe-rotatable system which tend todisplace the rotor plates from their true.-

1 in any suitable manner preferabl planes which should be parallel to the planes of the stator plates.

Having eliminated or at least reduced to a minimumthis mechanical difficulty, it will be apparent that the rotatable system will turn very freely, and due to the fact that in the design shown, the shaft 12 is somewhat oif-center with respect to the rotor plates, the rotatable system would not stay in adjusted tuning position over a considerable portion of the an ular movement. Therefore, I have provi ed a special adjustable means for applying to the rotatable system the necessary amount of friction to cause the rotatable system to maintain its adjusted tuned position.

This controllable frictioh is applied in the following manner:

The frame-work or more braces 27 which are positioned n and carried by the frame 1 between each of the condenser units. conform to the inner contour of the frame 1, or they may be cut out to some other desired shape. The brace 27 is provided with a notch 29, in which is positioned a .slotted end-30 of a'friction applying member 31. The member 31 is bowed downward at 32 under the shaft 12, and has a forked end 38 which slips over the topof the brace 27, all as shown in Figure 4:. An

adjusting screw 33 and lock nut 34 is pro.- vided to adjust the amount of friction which These braces 27 may eliminating the mechanical.

T have obtained a the center of 1 is provided with one I construction that may be used in the building of a single-unit condenser, but which is especially advantageous in the construction of gang condensers and which is substantially free from the troubles that have existed in previous designs. It is to be understood-that the shaft 12 any desired manner as for example, by a dial, drum, or other control means.

As shown in Figures 1 and 2, an electrical compensating condenser may be used. This comprises a single condenser plate 35 which is carried on the insulator 7 by the screws 11 and is thus electricall connected to each may be operated in stator group of plates. he position of the auxiliarycondenser plate 35 with respect to the frame 1', is adjusted by means of an adjusting screw 36 which passes through a clearancehole in plate 35. An insulator 37 of mica,- is positioned around the screw 36 etween the plate 35 and'the frame 1, so as to prevent the plate from being brought into contact with the frame 1, due

- to any adjustment of the plate 35. The

' member 31. The side pieces of the member 39 are adapted to pass downwardly over the sides of the braces 27 and may be spread to any desired degree to approach the rotor' plates 15, whereby the capacity of the condenser units adjacent the parts 39 may be slightly modified. It will be understood of course, that the auxiliary condenser 35 and compensating device 39 may both be used if desired.

In Figures 8, 9,'and 10, I have shown an individual separable bearing preferably of steel or metal sufficiently hard so as to present a smooth wearing surface of long life to the balls. In some cases it may be desirable to make the entire frame and the end support members 2 and 3, of brass, aluminum, or die-cast material, and particularly when'the latter is used, it is preferable to use a ball race of harder and better wearing material. Therefore, I have designed a separable race 45 which may be attached to the support members 2 and .3 in any suitable manner as by screws passing through the holes 46. This arrangement is especially adapted for use if the end support members 2 and 3 are made of insulating material.

If the frame and end support members are made of die-casting, then I prefer to mould, the race 45 directly to the frame structure, and to this end notches 48 are used for the moulding material to flow into, to hold the bearings securely in position.

As shown in Figures 8, 9, and 10, 47 illustrates the seat for the balls, and 49 is the reverse side of these ball seats or races.

In Fi ure 11, I have shown a construction I in whic the shaft 12 passes all the Way' through the end bearing support 2, which construction may be desired for the purpose of attaching some other piece of apparatus to the shaft 12. When this construction is used, the ball race 19 in the shaft 12, is posi tioned so that the balls engage'the race'17 at the point 50 andthe fshaftf12 and balls are held in proper workin position by means of a plate 41 held to t e end support member 2 by screws 20. In some cases it may be desired to make the special plate 42, as shown in Figure 12, somewhat more 'resilient than the shown in Figure 6, and to this end I have cut away part of the metal, as indicated at balls 18. Asshown'inFigure 12, the plate 42'is attached to the end support member plate 41 or the plate 21,

From what has been said, it will be read-- ily appreciated that certain of the details entering into the construction of my new and improved gang condenser, may be varied considerably without departing from the spirit of my invention or the scope of the appended claims; for example, a bearing support plate may be used between adjacent condenser units, for instance at the center of the condenser shown in' Figure 1, and equipped with a ball race just the same as the end support member 3, and the shaft also provided with a ball race, thus providing an intermediate bearing.

Having thus described my invention, what I claim is:

1. An electrical condenser having a frame with end support members, at least one group of stator plates carried by said frame and a rotatable system including a shaft carried by said support members and carrying a group of rotor plates for cooperation with the group of stator plates, said end support members and the shaft having parts formed in each for andeach carrying a plurality of anti-friction bearing devices, an en agement member for positioning said an'tiriction bearing devices in one of said support members, a cover plate for holding said engagement member in working position, an adjusting device carried by said cover plate for holding said shaft in longitudinal alignment,

and adjustable means for applying a debers and carrying a'plurality of groups of rotor plates corresponding in number to and for cooperation with the groups of stator plates, said end support members and the shaft having parts formed in each for and carrying anti-friction bearing devices, a brace plate supported by the frame between at least two groups of stator plates, and an adjustable device carried on and engagingia part of the rotatable system for applying a desired amount of friction to said rotatable system.

3. An electrical condenser having a frame with end support members, a plurality of groups of stator plates carried by said frame and a rotatable system including a shaft carried by said support members and said brace plate friction bearmg'members, means on the rear carrying a" plurality of groups of rotor plates corresponding in number to and for cooperation withthe groups of stator plates, said end support members and the shaft having parts formed in each for andcarrying anti-friction bearing devices, a brace plate supported by the frame between adjacent groups of stator plates, a device mounted on each brace plate having a part extending into frictional engagement with said shaft, and means for adjusting each of said devices to secure the desired amount of friction on said shaft.

4. An electrical condenser having a frame with end support members, a plurality of groups of stator plates carried by said frame and a rotatable system including a shaft carried by said support members and car-' rying a plurality of groups of rotor plates corresponding in number to and for.co-

operation with the groups'of stator plates, said end support members having seats formed therein for anti-friction bearing members, said shaft having an annular groove near its drive end to receive and hold said anti-friction bearmg membersv in the seat in the front end support member,

said shaft also having its inner end formed into a bearing race to cooperate withthe seat in the rear end support plate to receive antiend support member to hold the shaft and bearing members in working position,v a

brace plate between at least two'groups of stator plates, and an adjustable device carried on said brace'plate and engaging a part of the rotatable system for applying a desired amount of friction to said rotatable system.

5. An electrical condenser having a frame with end support members, a plurality of roups .of stator plates carried by said ame and a rotatable system including a shaft carried by said support members and carrying a plurality of groups of rotor plates corresponding in number to and for cooperation withthe groups of stator plates, said end support members having seats formed therein .for anti-friction bearing members, said shaft having an annular oove near its drive end to receive and old said ant1-fr1ct1on bearing members in the seat in the front end supportmember,

said shaft also having its inner end formed into a bearing race and extending ust through the wall of the bearing seat in the rear end support member whereby the shaft race can cooperate with the seat to receive anti-friction bearing members, a member engaging and holding the said bearing members in working position, a plate on the outer face of the rear end support member for covering said bearing seat, adjustable means carried by said plate for holding said engaging member and said shaft in operative position, a brace. for the frame positioned between adjacent groups of stator plates, a device mounted on at least one of said braces and having apart extendin into frictional engagement with said sha and means for adjusting said device to secure the desired amount of friction on said shaft.

6. An electrical condenser having a frame with end support members, a plurality of groups of stator plates carried by said frame and a rotatable system including a shaft car-' ried by said support memberscand carrying a plurality of groups of rotor plates corresponding in number to and for cooperation with the groups of stator plates, said end support members having ball races formed therein, said shaft having ball races formed thereon for cooperation with the first-mentioned races, balls in said races, a cover plate for the ball race in the rear end support member, a member engaging the balls positioned in the last-mentioned race, adjustable means carried by said cover plate for holding said engaging member and said shaft in operative position, a brace for the frame positioned; between adjacent groups of stator plates, a'device mounted on at least one of said braces and having a' part extending into frictional engagement with said shaft and means for ad usting said device to secure the desired amount of cure the desired amount of friction on said shaft. 7

8. An electrical condenser having a frame with end support members, a plurality of groups of stator plates carried by said frame, a shaft carrying groups of rotor plates for cooperation with. said stator groups, said shaft being supported by said end support members, means for reducing to a minimum frictional resistance between the shaft and said end support members,

said means'comprising anti-frictional bear ings for the shaft, a brace between at least two groups of stator plates, a device mounted on said brace and having a part extend ing into frictional engagement with said shaft, and means for adjusting said device to secure the desired-amount of friction ton said shaft.

9. An electrical condenser having a frame with end support members, a plurality of oups of stator' plates carried b said rame, ashaft car g roups o rotor plates for. cooperation with said stator groups, said shaft being supported b said end support members, means for re ucing to a minimum frictional resistance between the shaft and said end' sup ort members, said means comprising antirictional bearings for the shaft, both ends of said bearings comprising race-ways carried by each- 7 of said end supports and cooperating raceways formed directly in the shaft, the raceframe with end support members, antifriction bearing races positioned on said end support members,a plurality of groupsof stator plates carried by said-frame, a rotor system including a shaft carrying groups of rotor plates for cooperation with said statorgroups, races formed in said shaft to cooperate with the first-mentioned races,

a plurality of anti-friction members positioned in each of said races, the race at one end of said shaft'being formed directly at the end thereof, and means carried by the cooperating end support for directly engaging said anti-friction members tohold the same and the shaft in longitudinal align ment, and adjustable means for applying a rality of groups of stator said frame, a shaft carrying groups of,rotor" desired amount of friction independent of said shaft bearings to said rotor system.

11. An electrical condenser having a frame with end support members, a plurality of groups of stator plates carried b said rame, a shaft carrying groups 0 rotor plates for cooperation with said stator groups, said shaft being supported by said end support members, means for reducing to a mlnimum frictional resistance between the shaft and said .end support members, said means comprising ball-bearing races positioned on said end support members and cooperating races formed in said shaft withballs in-said races;,a cover plate for at least one of said pair of races to hold the shaft races and balls in working position, and adjustable means for applying a desired amount of friction to said shaft.

12. An electrical condenser having .a frame with end support members, a pluplates carried by.

plates. for cooperation with said stator groups, said shaft being supported b said M the shaft and said end support members,"

end support members, means for re ucing to a mlmmum frictional resistance between said means comprising ball-bearing races positioned on said end support members and cooperating races formed in said shaft with balls in said races; means for holding the shaft races and balls in working position, a brace between at least two groups of stator plates, a device mounted on said brace and having a part extendin into frictional engagement with said shaft, and means for adjusting said device to secure the desired amount of friction on said shaft.

13. An electrical condenser having a frame with end support members, a plurality of groups of stator plates carried by said frame, a shaft carrying groups of rotor plates for cooperation with said stator groups, said shaft being supported b said end support members, means for re ucing to a minimum frictional resistance between the shaft and said end support members, said means comprising ball-bearing races positioned'on said end support members and cooperating races formed in said shaft with balls in said races; a resilient cover plate for at least one of said pair of races-to hold the shaft races and balls in working position, a brace between adjacent groups of stator plates, a device mounted on each brace and having a part extending into frictional engagement with said shaft, and means for adjusting said devices to secure the desired amount of friction on said shaft.

14. An electrical condenser having a frame with end support members, a plurality of groups of stator plates carried by said frame, a shaft carrying groups of rotor' plates for cooperation with said stator groups, said shaft being supported by said endv support members, means for reducing to a minimum frictional resistance between the shaft and said end support members, said means comprising separable ball races adaptedto be attached to each end support member, races formed in said shaft to cooperate with the first-mentioned races, balls positioned in said races, means for holding the shaft races and balls in working position, a brace between at least two groups of stator plates, a device mounted on said brace and. having a part extending into frictional engagement with said shaft, and means for adjusting said device to secure the desired amount of friction on said shaft. 15. An electrical condenser having a frame with end support members, at least one group of stator plates carried by said frame, a rotatable system includin a shaft carrying a group of rotor plates for cooperation with the stator plates, separable anti-friction races attached to each end support member, races formed in said shaft to cooperate with the first-mentioned races, anti-friction bearing members positioned in said races, means including an engagement member having its outer edge formed into a rim to lap over the outer periphery of said anti-friction'members', and an engagement membervcarried by the rear end support to hold said en agement member in position,

thereby holding the shaft races and balls in working position, and adjustable means for applying to the rotatable system the desired amount of friction.

16. For an electrical condenser having a frame with end support members, a ,plurality of groups of stator plates carried by said frame, a shaft supported by, said end support members and carrying groups of rotor plates for cooperation vwith said stator" groups; means for specially supporting said shaft on said end support members, said special means consisting of, a race-way carried by each end support, and cooperating race-ways in the shaft ,with anti-friction members in said race-ways, thecondenser being further characterlzed in having a pressure exerting device comprising a resilient sheet of metal having a' central orifice through which the shaft projects, the metal of saidsheet around the orifice acting as a partial ball race, said sheet having cut-out sections be 0nd .the edge of the orifice whereby sa1d sheet is rendered more resilient, so that substantially uniform pressure.

. special means consisting of, a race-way carried by each end support, and cooperating race-ways in the shaft with anti-friction membersiin said race-ways, and adjustable support members, integral. means mechanically bers and having portions extending upwardly on opposite sides of the condenser, supporting tie bars, stator plates secured to said bars, and a single flat strip of insulation connected between each of said bars and said means, said strips of insulation being secured at a single end to said upwardly extending portions of said means, and at the other end to the supporting tie bars.

20. A variable condenser including; end support members, frame parts mechanically connected to and between said members and having portions extending upwardly on opposite sides of the condenser and having openings formed therein, supporting tie bars, statorplates secured to said bars, and a single fiat strip of insulation connected between each of said bars and said frame parts, said strips of insulation being secured connected to and between said mem at a single end to said upwardly extending portions of the frame parts and extending into said openings and connected at the other end to said supporting tie bars exposed by said openings.

- In testimony whereof, I afiix my signature.

STANLEY CRAMER.

means for applying to the rotatable system i i a desired amount of friction.

18. An electrical tuning device including a frame with end support members, a plurality of groups of stationary tuning members carried by said frame, a movable system comprising a shaft supported by said end support members and carrying groups of tuning elements for cooperation with said stationary tuning elements; means for specially supporting said shaft on saidend support members, said special means consisting of, a race-way carried by each end support, and coo erating' race-ways in the shaft with antiriction members in said race-ways, and means for movable system a :'desire friction.- 19. A variable condenser including; end

amount of applying to the so i CERTlFlCATE or CORRECTION.

Patent No. 1,800,7l9. Granted Abril 14, 193.1, to

STANLEY s. 'CRAMER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 17, for the word "turned" read tuned; page 5, line 9, claim 9, strike out the words "both 4 ends of" and insert same to follow the wordv "for" in same line and claim; and

l that the 'said Letters Patent should be read with these corrections therein that the same may conform to the record of thecase in the Patent Office.

Signed and sealed this 12th day of May, A. D. 1931.

- I M. J. Moore, (Seal) 0 1 Acting Commissioner of Patents.

DISC LAIMERv 1,-800,719.-Stanley S. Gramer, Haddon Heights, N. J. ELECTRICAL CONDENSER.

' Patent dated April 14, 1931. Disclaimer filed August 29, 1936, by the 'patentee;the-ass1gnee, Condenser Development Corporation, consenting. Hereb enters this disclaimer to claims 19 and 20 of said patent.

Gazette'September 29, 1936.] 

